Typically, a single-sided, single-sheet touchscreen is configured such that upper and lower substrates respectively having conductive patterns formed thereon are laminated together, with an insulating layer being interposed therebetween. The manufacture of such a single-sided single-sheet touchscreen includes forming a metal mesh pattern, forming an insulating layer, and forming a bridge electrode. As for a single-sided single-sheet touchscreen, x- and y-axis mesh patterns are formed on the same surface, and the x-axis mesh patterns are interconnected to each other but the y-axis mesh patterns are disconnected. Since the x- and y-axis patterns must be separated from each other, a single-sided single-sheet touchscreen requires an insulating layer for separating the x-axis and y-axis patterns. In order to connect the disconnected y-axis patterns after formation of the insulating layer, an overbridge electrode is formed using a transparent electrode composed of a conductive polymer or a silver (Ag) nanowire.
However, the metal mesh substrate and the insulating layer have different surface energies, and thus when the transparent electrode pattern is formed, the line width and thickness of the transparent electrode are not uniform on the metal mesh substrate and the insulating layer. This is because, due to the difference in surface energy between the metal mesh substrate and the transparent insulating layer, the contact angles defined by ink for the transparent electrode on the above two materials are different. Accordingly, there is a need for an insulating layer for forming a transparent electrode in a uniform pattern while separating the connected metal meshes oriented in a transverse direction (x-axis) from the y-axis metal meshes.
In this regard, Korean Patent Application Publication No. 2012-0031896 discloses the formation of a conductive layer for connecting electrode layers in the formed recess using an inkjet printing process, but is problematic in that the pattern for the insulating layer cannot be formed to a uniform line width and thickness.